Electron discharge device



Jan. 13, 1953 H. G. ANDERSON 9 ELECTRON DISCHARGE DEVICE Filed Feb. 1, 1947 a 45 44 4/ 43 5 3s 4342444 W %/%/W%W/W k I I u u k E g E 1 Z 5 J lz a M 37 ATTORNEY v Qheof theiibiects-o'ft pie, at east as she-"ream see not.

"so "construct the aliov' Patented Jan. 13, 1953 ITE D S TATES PATENT 2,625,669

*niscHARGE DEVI-es *ntmer "G Anderson,:Newtonville, Mass asslgn'or :tg'RaytheonManufaeturingCompanm-Netvton, 'Mass:, a corporation of Delaware safistazoaifirtrtnt 1, 19h, soar-miser es 1 7 This invention relates to electron discharge devices and, more particularly, to tuhableelectron discharge devices, i v a Whilenot 'liinit'd em themes-eat invention especially s u ie C r l ini; "electron discharge devices "'of the so=called magnetron type.

preseht. i'nventi-o'n is to provide means "for tuning a e ect on discharge device through a substantial fieo iency range, aha by "siihstantialf rrequeiiey ra ge is me nt a rahge; which the maximum frequency deviation represents an appreciable percentage "of "the natural fred'ue'ncy 'Qt'the device, ioteXambill ll. 10% 70 21100 116 40%"Of Knotherobjct of the' pgesentinvention is to so the frequent dev ation"optamedtnereb is contiii'iious 'a'nd substantially-linear. 'A'furth'erobj'cto the present invention is to entionea tuning-means to overcome any tendency o introduce spurious ds cillaliiofis the device "being tuned,

These and other objects will become more appali'entas the'det'ailed deseription of the-present invention progresses and by referenee to the'accompanyine drawing in which: V V

Fig. l'i-s a "sectional view "taken through the center of a tunablehiagiietronconstriictedfin accordance with the principles of the present invention. l v

Fig. 2 is a rrag'm ntarysectional view in pereffective or evera1 or't'h anoiie'm'mbers of "the device shown in Fig. '1,

liis'tratiiig the physical relationship between *said anode in'emher and the tuning meahs;and

Fig. I 3 is a perspective view of the tuning means made in accordancewith the principles'b'f the present invention.

Referring now more particularly to the'aforesaid illustrative embodiment of'the present invention, and with partic'ular f'refereiice to the drawing showing "same, the niiine'ral l'fleenerally designates the envelop'e of anelectron discharge device of the so-called niagrietrontvpe. Said envelope is hermetically-sealed bi fa pairfof caps I I *and I 2. Preferably, theaforeinenti'oned items ntermediate has that the xis of s'ai'd envelope.

1s---partibu air 'mbo diinent,

is integral withfs'aid envelope and eonsists of a plurality of radi'ally disposedrinteriorlwextending anode mernhers inthe' form of "vanes "I 6, each adjacent pair'ofvan'es, together with that-portion of the envelope l lying therebetweenydefining the walls of "a =cavitv reso'nator 'who'se natural resonant "frequency as is "well "known in the art to which the present invention relates, a func- "it which are adjacent-the wall -of the envelope,

the annulus i5 being disposed similarly with respect to the lower end of said anodes [6. It has been found that the -particular"arrangement of the annuli 13,14 and" i5 overcomesspurious 0sci'llations in therespectivespaces adjacent the caps II and I2. 7

Apertures I! and l 8 are provided-in-said envelope 10 for the 'insertionoflcathode lead-in conductors, and for the sake-ofelarity saidoathode lead-in conductors and'the cathode structures are omitted. -A-third aperture I9 is also provided in said envelope for; the insertion of; an "energy pick-up loop, and is also-omitted- --fer the same "reason. Reference; may Joe had to "a copending application-of Willia nCF-Bmvm, Serial No. 583,624; filed March -19,g1 94-5 ,;-in which isillustrated the disposal of-a cathode-structure and pick-up "100p within en-electron discharge clevice of the type hereimdescribed in connection with thepresentinvention. 7

Each anodemember I6 is provided, preferably, in both itsupper and'lower edges,-see Fig. 2, ad-

jacent'its inner end,- with cut-away portions-or 25 and 26'is concentrically disposedwith respect to each other \VithiHfthBSlOtS 20. The straps 25 and 26are provided,respectively, with extensions or legs 21 and--28andMesa-spaced that, when attached 'to'the bottoin'e'dges 22 of the anode membersifi, said' -straps "clear said bottom 'edgesof each alternate ariode'inernberas clearly illustra'tedinFig.--2.

The straps 25 and "ZB Whe'nthus' dispo'seo with respect to each other preseht'aicapaoitance therebetween whiehentersinto thedetermination of the natural frequ'e'n of'-'the"device.

The lower slots "2 f are shallower-and narrower 3. than the upper ones and a second pair of conducting straps 21-28 is concentrically disposed, with respect to each other, in said lower slots. They are attached in a similar manner as the straps 25-26. The straps 21-28 are spaced closer together than the straps 25-26 and establish, in this particular embodiment, the natural or lowermost resonant frequency of the device. This particular construction provides considerable latitude in the selection of a natural resonant frequency without the necessity of constructing a larger envelope to provide a device having, for example, a longer wavelength.

Attention is called to the construction of the straps 25-26. See Fig. 2. The height of these members, it will be noted, extends above the opening of the slots 23 for reasons that will be presently explained.

Inasmuch as the straps of each pair thereof have a capacitance therebetween, they may be considered the plates of a capacitor, and, by varying this capacitance, and introducing additional capacitance in parallel therewith, the device can be tuned, and to this end there is provided the following:

A stud 29, made of highly conductive material, such as copper, is constructed integral with a pair of supporting arms 30 which in turn are made integral with an annulus 31, see Fig- 3. Said annulus, when caused to move, for example, intermediate the straps 25-25, constitutes, together with said straps, a variable capacitor. In order to maintain the device air-tight, there is provided an apertured flexible diaphragm 32, hermetically sealed, at its periphery, to the cap i2, and similarly sealed, at its central aperture, to the stud 29.

The introduction of the annulus 3| into the space between the straps 25-25 does two things. First, it reduces the effective area of the surfaces of said straps between which the above-mentioned capacitance exists, but, inasmuch as this capacitance is small to begin with, the overall eifect on the frequency is likewise small. Second, it forms, together with said straps, two capacitors, connected in series, which did not, before, exist. Since the gaps between said annulus and straps are small, the total capacitance of the newly-formed capacitors is relatively large, and this capacitance, added in parallel with what remains of the original capacitance, has a considerable effect upon the frequency of the device.

As pointed out hereinbefore, the straps 25-26 extend above the anode slots 20. It has been found that by this arrangement there is secured a continuous frequency deviation and linear tuning, under conditions where such, heretofore, has been unattainable, and over a substantially greater frequency range than has heretofore been possible.

The annulus 3|, see Fig. 3, is provided with a discontinuity 33, located substantially midway of the supporting arms 33, to provide clearance for the insertion of the cathode lead-in, not shown, within the aperture ll. Proper positioning of the supporting arms 30 must be provided to avoid the introduction of spurious oscillations. To this end, said arms are attached to points on said annulus along a chord other than the diameter thereof, and preferably the arc of the annulus which includes the discontinuity 33 should be greater than the are opposite thereto.

While not limited thereto, the tuning control means are constructed as follows.

Secured to and surrounding the stud 29 is an externally-threaded bushing 34. While the illus: trative embodiment indicates the use of a threaded bushing, the stud 29 can itself be threaded if so desired. Said threaded bushing 34 engages an annular member 35 whose periphery is provided with a V-cut constituting a ball-bearing race. Said ball-bearing race is secured to a disk 36,- the periphery 31 thereof constituting a ring gear. Said ring gear engages a pinion gear 38, said pinion gear being actuated by a shaft 39 secured thereto in any suitable manner. Surrounding said flrst-named ball-bearing race is another race comprised of two cooperating bevelled rings fill-4|, the ring 40 being supported by an annular shoulder provided for on the cap I2, and the ring 4! being urged into cooperation with the ring 40 by a pair of annular springs 42. The aforementioned races are receptive therebetween of bearing balls 43, and the springs 42 are secured 305 the cap l2 by a flat retaining ring 44 and bolts Manipulation of the pinion gear 38 through its associated shaft 39 imparts rotation to the disk 36 via the ring gear 31 integral therewith. As a result, the threaded ball-bearing race 35 which is fastened to said disk by the bolt 46 and threadedly engaged with the tuning stud 29 imparts a linear, motion to said tuning structure 33-3! and thus varies the capacitance between the straps 25-25.

This completes the description of the aforesaid illustrative embodiment of the present invention. From the foregoing it will be noted that there is provided relatively simple means for tuning an electron discharge device, particularly a magnetron, through an appreciable frequency range. It will also be noted that the frequency deviation thereby obtained is continuous and linear and that the particular construction of the tuning structure provides a device, free of spurious oscillations. It will be obvious, however, that the present invention may be modified to meet various conditions which may be met in different specific uses, and it is, therefore, intended to cover by the appended claims all such modifications which fall within the spirit and scope of this invention.

What is claimed is:

1. A tunable electron discharge device comprising: an anode structure provided with a plurality of anode members; a first annular conductor electrically connected to one anode member of one adjacent pair thereof; a second annular conductor electrically connected to the remaining anode member of such adjacent pair thereof; said conductors presenting a capacitance therebetween; a third annular conductor, spaced from and movable intermediate said conductors, for altering said inter-conductor capacitance and connecting, in parallel therewith, an additional capacitance; and a strap-like member, connected to said third annular conductor at two points along a chord other than the diameter thereof, supporting said third conductor with respect to said first and second conductors.

2. A tunable electron discharge device comprising: an anode structure provided with a plurality of radially disposed anode members; each anode member having a slot formed therein; a pair of annular conductors disposed in each such slot and alternately contacting successive anode members; said conductors presenting a capacitance therebetween; a third annular conductor, movable intermediate said first and second conductors, for altering said inter-conductor capacislot and alternately contacting successive anode members; said conductors presenting a capacitance therebetween; a third annular conductor, movable intermediate said first and second conductors, for altering said inter-conductor cap'aci-' anode structure provided with a plurality of radially disposed anode members; each anode member having a pair of. .slots formed therein, said slots being oppositely disposed with respect to each other; and a plurality of pairs of conductors disposed, respectively, in said oppositely disposed slots, one of said pairs of conductors being spaced closer together, with respect to each other, than the oppositepair of conductors.

6. A tunable electron discharge device comprising: an anode structureprovided with a plurality of radially disposed anode members; each anode member having a pair of slots formed therein, said slots being oppositely disposed with respect to each other; a plurality of pairs of conductors tance and connecting, in parallel therewith, an additional capacitance; said third annular conductor having a discontinuity in the periphery thereof; and means, connecting two points on said third annular conductor along a chord other than the diameter thereof, supporting said third conductor with respect to said first and second conductors.

4. A tunable electron discharge device comprising: an anode structure provided with a plurality of radially disposed anode members; each anode member having a slot formed therein; a pair of annular conductors disposed in each such slot and alternately contacting successive anode members; said conductors presenting a capacitance therebetween; a third annular conductor, movable intermediate said first and second conductors, for altering said inter-conductor capacitance and connecting, in parallel therewith, an additional capacitance; said third annular conductor having a discontinuity in the periphery thereof; and means, connecting two points on said third annular conductor along a chord providing an are on that side of said chord including said discontinuity which is greater than the arc opposite thereto, supporting said'third conductor with respect to said first and second conductors.

5. An electron discharge device comprising: an

disposed, respectively, in said oppositely disposed slots, one of said pairs of conductors being spaced closer together, with respect to each other, than the opposite pair of conductors; said pairs of conductors presenting a capacity therebetween; and means, movable intermediate said further spaced conductors, for altering said inter-conductor capacitance and connecting, in parallel therewith, an additional capacitance.

HOMER G. ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,399,223 Haeif Apr. 30, 1946 2,414,085 Hartman Jan. 14, 1947 2,418,117 Hale et a1. Apr. 1, 1947 2,422,465 Bondley June 1'7, 1947 2,443,445 Donal. Jr. June 15, 1948 2,444,419 Bondley July 6, 1948 2,448,573 Blazier et a1 Sept. 7, 1948 2,468,243 Spencer Apr. 26, 1949 2,481,171 Spencer Sept. 6, 1949 2,485,084 Brown Oct. 18, 1949 2,509,419 Brown May 30, 1950 2,542,908 Derby Feb. 20, 1951 

